Amino acids, also called the building blocks of proteins, are compounds that perform a wide range of essential functions in the body. They are required for vital processes such as protein building and the synthesis of hormones and neurotransmitters.
Some may also be taken in supplement form to naturally enhance sports performance or improve mood. They are categorised as essential, conditionally essential or non-essential, depending on various factors.
Essential amino acids
Essential amino acids are substances that our body cannot produce itself and must be obtained through food or supplements. Your body needs 20 different amino acids to grow and function properly. Although these 20 amino acids are important for your health, only nine are classified as essential. These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Conditionally essential amino acids
Your body needs and can synthesise conditionally essential amino acids (also called semi-essential amino acids) itself from other building blocks. But sometimes these are in short supply, e.g. when the daily diet is insufficient or in case of health problems such as illness, injury or after an operation. A supplement may be advisable or even necessary. Semi-essential amino acids are: arginine, asparagine, glutamine, glycine, serine and proline.
Non-essential amino acids
Non-essential amino acids can be produced by our body (the liver) itself from other amino acids, if the body lacks a non-essential amino acid for the production of a particular protein. Non-essential amino acids are: alanine, aspartic acid, cysteine, cystine, glutamic acid, tyrosine and hydroxyproline.
Their roles in your body
The 9 essential amino acids fulfil a number of important and diverse tasks in your body:
Phenylalanine is needed for the production of the neurotransmitters dopamine, adrenaline and noradrenaline in your brain. These neurotransmitters have important functions in the body and allow nerves to communicate and send signals to each other. Dopamine is involved in rewarding behaviour and experiencing pleasure. This is why we also call it the 'happiness hormone'.
Valine is one of three branched-chain amino acids (the others being leucine and isoleucine) that increase energy, boost endurance and help repair and rebuild muscle tissue. This group also lowers elevated blood sugar levels and increases growth hormone production. These three branched-chain amino acids are often taken in combination in the form of a BCAA supplement.
Leucine is valuable as a stand-alone amino acid supplement to promote muscle building and recovery. To further optimise muscle building and recovery, it plays an important role. Leucine enhances the muscle-building stimulus in muscles.
Isoleucine is the last of the 3 branched-chain amino acids and, among other things, regulates blood sugar levels in the body and the production of haemoglobin. This amino acid is also necessary for muscle recovery after exercise and is also important in metabolism to produce energy.
Threonine is an important component of dental tissue, collagen and elastin in the skin. It is also an important amino acid for the nervous system, fat metabolism and liver function. It combats fatty liver.
Tryptophan plays a role in the production of the neurotransmitter serotonin. This substance affects mood, self-confidence, sleep, emotion, sexual activity and appetite. L-Tryptophan can promote sleep, diminish anxiety and act as an antidepressant.
Methionine is a unique amino acid and has an important function in the production of proteins in cells and muscles. It contains sulphur and can make other sulphur-containing molecules in the body that provide tissue and DNA protection in cells.
Lysine is important for the production of enzymes, hormones and antibodies as well as bone and collagen. It is abundant in muscle tissue and helps the absorption of calcium from the intestines. Its most outstanding property is its action against viral infections in a general sense.
Histidine is mainly involved in growth and tissue repair. Histidine is further important for the myelin sheath that protects nerves. Furthermore, histidine is transformed into histamine. Histamine affects many functions, including immunity, gastric secretion and reproduction. Because your body only produces Histidine in very small quantities, you need to get it from food or supplement it with a supplement if necessary.
Health Benefits of Amino Acid Supplements
While essential amino acids can be found in a wide range of foods, taking concentrated doses in supplement form has been linked to several health benefits.
Promote the rate of protein synthesis
Preserve muscle mass
Promote the production of new cells
Provide the body with energy
Help reduce fatigue as they inhibit serotonin production
Improve muscle growth
Assist in the production of strong connective tissue and the growth of healthy bones
Help with wound healing and recovery
Complete protein sources
Foods containing all 9 essential amino acids are called complete protein. Incomplete sources lack one or more of the essential amino acids.
Animal proteins are always complete proteins, but there are also plenty of complete vegetable protein sources such as quinoa, buckwheat, amaranth, spirulina, hemp seeds and chia seeds.